87990009978 has 32 divisors (see below), whose sum is σ = 189528478272. Its totient is φ = 27072201600.

The previous prime is 87990009973. The next prime is 87990010067.

87990009978 is nontrivially palindromic in base 10.

It is not an unprimeable number, because it can be changed into a prime (87990009971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2104093 + ... + 2145503.

It is an arithmetic number, because the mean of its divisors is an integer number (5922764946).

Almost surely, 2^87990009978 is an apocalyptic number.

87990009978 is an abundant number, since it is smaller than the sum of its proper divisors (101538468294).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

87990009978 is a wasteful number, since it uses less digits than its factorization.

87990009978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68670.

The product of its (nonzero) digits is 20575296, while the sum is 66.

The spelling of 87990009978 in words is "eighty-seven billion, nine hundred ninety million, nine thousand, nine hundred seventy-eight".